1. Field of the Invention
The present invention relates generally to certain improvements in quick disconnects and more specifically, to certain improvements in the geometrical parameters of quick disconnects which produce surprising results, namely, unexpected significant reduction in fluid pressure drop across teh quick disconnect.
2. Prior Art
Quick disconnects are well-known in the art. They are commonly used to interconnect one flexible pipe to another flexible pipe, both of which pipes are adapted for the flow of a fluid therethrough. The term "pipe" as used herein means any type of fitting, hose, boss, etc., to which a quick disconnect may be attached. The term "quick disconnect" is derived from the performance characteristics of this type of connector. More specifically, a quick disconnect is adapted to permit disconnection of the two fluid carrying pipes with a self-sealing feature designed so that little or no quantities of the fluid escape the connectors upon disconnection. Furthermore, the process of disconnecting the two pipes can be implemented by simple mechanical release of a portion of the body of the quick disconnect without the necessity for disconnecting or unfastening a plurality of conventional fastening elements such as bolts and the like. Some self-sealing quick disconnects may require the use of a wrench.
Although it can be readily understood that such a quick disconnect apparatus is highly advantageous for the aforementioned purpose, one disadvantage is that inherently the placement of virtually any kind of connector in the path of fluid flow that restricts the flow path causes an undesirable pressure drop. In most cases there has been a trade-off between the extent of such an undesirable pressure drop and the size of the quick disconnect apparatus. More specifically, those having skill in the art to which the present invention pertains generally believe that the larger the quick disconnect apparatus, the smaller is the pressure drop thereby reducing the disadvantages of such quick disconnect apparatus from the standpoint of pressure drop. This has been disproven by the research relating to the present invention. The larger quick disconnect theory is accurate up to approximately 2.5 times the pipe flow area. If the area grows larger than this, the pressure drop will actually increase. This is due to two different actions. If a quick disconnect is made so that it is to standard commercial length but larger in diameter, the interconnecting angles will be extreme, causing fluid separation, and velocity deceleration upon diverging, and excessive boundary layer friction upon converging. This results in high pressure loss. Conversely, if a quick disconnect is made so that it is standard in diameter but very long, the resulting boundary layer friction (even while diverging) will increase the pressure drop. The reason that the larger quick disconnect theory has persisted is because the pressure drop resulting from an oversize quick disconnect is not nearly as great as the pressure drop of a small quick disconnect not using the novel geometric principals disclosed herein. An increase in the size of the quick disconnect apparatus results in at least a commensurate increase in the costs thereof which is also a significant disadvantage. In the aerospace industry in which this invention finds particularly advantageous application, weight is a concern equal to or greater than cost. Accordingly, there has been a long-felt need for a quick disconnect apparatus of the type having improved pressure drop characteristics so that either the pressure drop through a specific size quick disconnect can be reduced or for a specified pressure drop across the quick disconnect apparatus, the size of the quick disconnect can be reduced.
Virtually all quick disconnects comprise two major members called a "coupler" and "nipple", respectively. Each such member is designed to mate with a corresponding fluid carrying pipe and then to be mated with each other so that the respective pipes can be interconnected. The nipple may be regarded as the male member in that it slides into the coupler. Typically, the nipple comprises a spring loaded poppet and the coupler comprises a stationary stem. When the coupler and nipple are mated, the coupler stem is designed to engage the nipple poppet, pushing it away from the interface of the two members whereby to permit fluid flow around the poppet of the nipple as will be hereinafter more fully described. In addition, when the two members are interconnected, the nipple body slides into the coupler body so as to depress a spring loaded cylinder called the coupler poppet, the depression of which allows fluid flow through the coupler as well. This generalized description of the major components of typical quick disconnect apparatus is provided herein primarily for purposes of background. The specific structural details of the quick disconnect of the present invention as well as the advantageous improvements thereto will be provided hereinafter.